Astronomers recently got their hands on Gemini Observatory’s revolutionary new adaptive optics system, called GeMS. “And the data are truly spectacular!” said Robert Blum, deputy director of the National Optical Astronomy Observatory with funding from the U.S. National Science Foundation. “What we have seen so far signals an incredible capability that leaps ahead of anything in space or on the ground — and it will for some time.” Blum is currently using GeMS to study the environments in and around star clusters, and his preliminary data, targeting the spectacular cluster identified as RMC 136, are among the set of seven images being released. The remaining six images — spanning views from violent star-forming regions to the graceful interaction of distant colliding galaxies — only hint at the diversity of cutting-edge research that GeMS enables.

After more than a decade in development, the system, now in regular use at the Gemini South Telescope in Chile, is streaming ultra-sharp data to scientists around the world — providing a new level of detail in their studies of the universe. The images now being made public show the scientific discovery power of GeMS (derived from the Gemini Multi-conjugate adaptive optics System), which uses a potent combination of multiple lasers and deformable mirrors to remove atmospheric distortions (blurriness) from ground-based images.

Unlike previous adaptive optics (AO) systems, GeMS uses a technique called “multi-conjugate adaptive optics” (MCAO), which not only captures more of the sky in a single shot (between 10 and 20 times more area of sky imaged in each “picture”) but also forms razor-sharp images uniformly across the entire field, from top to bottom and edge to edge. This makes Gemini’s 8-meter mirror 10 to 20 times more efficient, giving astronomers the option to either expose deeper or explore the universe more effectively with a wider range of filters, which will allow them to pick out subtle yet important structural details never seen before.

“Each image tells a story about the scientific potential of GeMS,” said Benoit Neichel, who led the GeMS commissioning effort in Chile. According to Neichel, the targets were selected to demonstrate the instrument’s diverse “discovery space” while producing striking images that would make astronomers say, “I need that!”

The first data coming from GeMS are already making waves among astronomers across the international Gemini partnership. Tim Davidge, an astronomer at Canada’s Dominion Astrophysical Observatory, with funding by the Canadian National Research Council, studies populations of stars within galaxies beyond our Milky Way. His work requires extreme resolution to see individual stars millions of light-years away. “GeMS sets the new cool in adaptive optics,” said Davidge. “It opens up all sorts of exciting science possibilities for Gemini while also demonstrating technology that is essential for the next generation of ground-based mega-telescopes. With GeMS, we are entering a radically new and awesome era for ground-based optical astronomy.”

Stuart Ryder of the Australian Astronomical Observatory, with funding through the Australian Research Council, whose work requires crisp images of distant galaxies to reveal exploding stars (supernovae), also anticipates the potential of GeMS for his research. But mostly he’s blown away by the raw technology involved. “I was fortunate enough to witness GeMS/GSAOI in action, and I was awestruck by the sight of the yellow-orange laser beam piercing the clear, moonlit night,” said Ryder. “When one considers all the factors that have to work together, from clear skies to a steady stream of meteors burning up in the upper atmosphere sprinkling enough sodium atoms to be excited by the laser — it’s wonderful to see it all come together.”

Orion Bullets

The "Bullets" region of the Orion Nebula has a long history of adaptive optics (AO) imaging at Gemini. A smaller section of the field shown here was first targeted with the Altair adaptive optics system at Gemini North in 2007, followed by this much larger-field imaging sequence with the Gemini Multi-conjugate adaptive optics System (GeMS) at Gemini South. This near-infrared image is composed of three, 3-band pointings using GeMS with the Gemini South AO Imager (GSAOI).

In the GeMS/GSAOI image, strong winds from violent explosions associated with a region of star birth behind the Orion Nebula expel bullets of gas that created this spectacular system of molecular hydrogen wakes. Researchers and principal investigators John Bally and Adam Ginsberg of the University of Colorado are using their GeMS data to determine the intensity of the blast and the nature of the bullets. “Are they dense fragments of circumstellar disks? Could they be ejected protoplanets? Or are they portions of the prestellar core from which massive stars form?” Bally asked. “The sub-arcsecond resolution provided by GeMS is needed to resolve these shocks and to search for the compact, high-density knots responsible for these wakes.”

NGC 4038

This multiple pointing, 3-band, near-infrared image obtained with GeMS/GSAOI reveals remarkable, colorful details in NGC 4038, one of the components of the Antennae Galaxies (NGC 4038/NGC 4039), despite a short total exposure time.

The Antennae Galaxies are probably the most recognized pair of interacting disk galaxies in the sky. The popular name comes from the resemblance of their tidal tails to the antennae of an insect, as seen in the wide-field images. The starburst system, only about 10.5 million light-years distant, harbors a rich population of massive young clusters, whose formation has been triggered by the interaction. Considered to be globular cluster progenitors, these objects are resolved in remarkable clarity in the GeMS image of NGC 4038.

“The exquisite data provided by GeMS/GSAOI allows us to differentiate compact star clusters from individual stars, study their integrated-light properties, and set constraints on the underlying stellar populations,” said Gemini South staff astronomer Rodrigo Carrasco, who suggested this target for the System Verification process. “This gives us the ability to extend the study of the star clusters in interacting galaxies to much fainter brightnesses and with greater sharpness. The Antennae illustrate the possible future of our Milky Way when it collides with the Andromeda Galaxy billions of years from now.”

NGC 1851

NGC 1851 is an ancient globular star cluster some 40,000 light-years from our Sun. All globular star clusters have a very high density of stars. “Peering deep into them to look at the faintest stars requires high spatial resolution. It’s essential,” said Principal Investigator Alan McConnachie of Canada’s Dominion Astrophysical Observatory (formerly the Herzberg Institute of Astrophysics), who wants to obtain a better understanding of the cluster’s stellar population –– particularly of its age, any evidence for multiple stellar populations, and the distribution of low mass stars. “We want to push the capabilities of GeMS to the limit so that we can determine the internal dynamics of globular clusters and understand how best to use MCAO for precision astrometry and photometry,” he said. “After all, MCAO is a key capability for the future of ground-based astronomy through its use in the Thirty Meter Telescope, and GeMS is allowing us to peek into that future and get a head start!”

R 136

A single pointing, 3-band, near-infrared image, obtained with Gemini South’s GeMS/GSAOI of the star cluster and associate nebula R 136.

Despite years of study with the largest telescopes and best instruments, the nature of star cluster centers is not well understood. The best data to date from the Hubble Space Telescope on R 136, a local analog to starburst clusters in distant galaxies, are still incomplete. The crowded fields make it difficult to count all the stars in the core due to the extensive overlapping of suns. With GeMS, astronomers can now resolve most of R 136’s core down to one or two solar masses and determine if stars less massive than this prevail. “Having a wide field of view with uniform image quality makes such investigations easier and more accurate than could be done before,” said National Optical Astronomy Observatory’s deputy director, researcher, and principal investigator, Robert Blum. “Using GeMS, we can obtain the very best description of the stellar content of R 136 ever. Not until the next generation of large ground-based telescopes are built will we be able to do better.”

RCW 41

A single pointing, 3-band, near-infrared image obtained with Gemini South’s GeMS/GSAOI of the star cluster and associate nebula RCW 41.

RCW 41 is a star-forming region harboring a massive star cluster surrounded by dust and gas. It lies in the Vela Molecular Ridge –– itself a vast star-forming complex in the plane of our Milky Way Galaxy. By using the near-infrared capabilities of GeMS to probe deep into the obscuring dust that pervades this region, astronomers can study the physical processes acting on this complex environment. Principal Investigator Henri Michel Pierre Plana of Universidade Estadual de Santa Cruz in Brazil said, “With its high resolution of 0.13 arcsecond and high sensitivity in the near-infrared, GeMS/GSAOI turned out to be the ideal tool to study the distribution of the initial masses of stars in this young cluster, which can tell us much about their properties and how they evolve.”

NGC 2346

A single pointing, near-infrared image obtained with Gemini South’s GeMS/GSAOI of the planetary nebula NGC 2346.

Planetary nebulae are the gaseous remnants of low- and intermediate-mass stars. Evolved planetary nebulae, such as NGC 2346 (shown here), contain a variety of complex and poorly understood filamentary and clumpy structures. Principal Investigator Letizia Stanghellini of the National Optical Astronomy Observatory and colleagues utilized the high-resolution capability of GeMS to detect these features at scales that would reveal the physical processes leading to their formation. “From the observation point of view,” Stanghellini said, “such an analysis is possible only with the resolution afforded by GeMS/GSAOI. The data will enable us to explore the nature and evolution of planetary nebulae microstructure, and to study the molecular formation and destruction processes in great detail. This will greatly advance our understanding of chemical recycling in our galaxy and other stellar systems.”

Abell 780

This is a rich cluster of galaxies 840 million light-years distant. Better known as Hydra A, Abell 780 has been thoroughly studied at X-ray wavelengths, but its fine-scale structure has largely remained a mystery to astronomers at optical wavelengths. Recent studies, however, show the cluster to have a gravitationally bound structure of 27 galaxies and a more strongly gravitationally bound structure of 14 galaxies. This GeMS/GSAOI image shows the cluster”s core in unprecedented detail.

“Our goal was to explore the structure of these galaxies at sub-kiloparsec scales,” said Rodrigo Carrasco, GeMS System Verification Team, Gemini Observatory. “This will allow us to compare the structure of these galaxies with similar objects found in the early universe.” The team selected Abell 780 because not only is it nearby but its center is dominated by a very powerful radio galaxy, known as Hydra A (also 3C 218), which has a prominent radio jet normally not detected in optical images.

“Thanks to the exquisite resolution (sharpness) provided by GeMS and GSAOI,” Carrasco said, “we can see some features of the jet, including at least two knots in the infrared, which are not visible in the optical images at similar resolution taken with the Hubble Space Telescope.”

The image also shows a number of globular star clusters surrounding this main galaxy. Such details are not seen in images that don't use adaptive optics. “We can see also several galaxies in the field that have compact morphologies,” Carrasco said, “and with details that normally are seen only from space.”